1. Field of Invention
The present invention is related to scanning devices, particularly document scanners of the hand-held type, such as a mouse scanner.
2. Description of Related Art
A variety of document scanning devices exist in the art. They include fax machines, copiers, multifunction fax/copy/print devices, stand-alone flat-bed scanners and the like. A disadvantage to these types of devices is that they are large and not portable. So, the document to be scanned must be brought to them. Recently, small hand-held scanners have been introduced. Some are portable and stand-alone such as the VuPoint PDS-ST410-VP Magic Wand Portable Scanner. Others can be connected to a laptop computer such as the Xerox Travel Scanner 100. These types of scanners, however, are still large enough to accept a sheet of paper.
A more recent development is a very small scanner that scans only a portion of the document (e.g. a page of a book or a photo) as the scanning device is moved over the document. Image processing is used to stitch together these scanned portions to create a copy of the entire page or entire photo. U.S. published patent application no. US 2010/0124384 describes one example of this type of device. In some cases the devices operate in two modes; in one mode they operate as a conventional mouse and in another mode they operate as a scanner. Commonly owned U.S. patent application Ser. No. 12/648,236, filed Dec. 28, 2009, Publication No. 2010/0171996, and U.S. patent application Ser. No. 12/645,421, filed Dec. 22, 2009, Publication No. 2010/0165422, describe this type of device, sometimes referred to as a “mouse scanner.”
Some of the problems encountered in these types of small scanners that are moved by hand over a document are poor image quality and poor registration of the multiple scanned portions.